This study is designed to examine the historical demography and genealogies of the Utah Mormon population over a period of approximately 125 years, using materials maintained by the Genealogical Society of the Church of Jesus Christ of Latter-day Saints. Funds have been received (NCI Research Grant 16573) for the construction of the genealogies for Utah. In that project, a major task is the linking of all Mormon families whose children were born in Utah (or along the pioneer trail) to form a statewide genealogy which extends from 1830 to the present. The purpose of this grant is to provide the incremental funding to allow us to study the social, genetic and historical demography of this population. The goals are: 1. Describe basic demographic structure and changes. 2. To analyze mortality trends construct period and cohort life tables. 3. To investigate the reproductive process in a natural fertility population, using polygamy and consanguinity to separate biological and social components of heterogeneity. 4. To study marriage pools and models of marriage markets. 5. To investigate genealogies as a structural unit. 6. Correlation among relatives of demographic parameters. 7. To evaluate the coverage and quality of the Utah Mormon (Church of Jesus Christ of Latter-day Saints) genealogical records for demographic research. 8. To further evaluate the record linking system and computer routines being developed for the genealogical, genetic and epidemiological studies.